The invention described herein may be manufactured and used by or for the government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
Not Applicable.
1. Field of the Invention
The present invention relates generally to a machine for positioning an analytical device. More specifically, the present invention may be used to make propellant surface optical measurements. The measurements are used to determine the aging characteristics of rocket motor propellant.
2. Background
After missiles have been in the field or storage for long periods of time, it may be necessary to determine the dynamic properties of the propellant. There is currently a need for support devices capable of sensing the dynamic properties of rocket motor propellant over long periods of time without disturbing the integrity of the propellant itself. Any change in the dynamic properties of the rocket motor propellant may affect the performance of the rocket motor. As a result, rocket motor propellant is periodically inspected to ensure that the propellant is able to effectively perform its required function.
One common problem of storing various propellants is the migration of nitroglycerin around the liner of a rocket motor casing. The periodic measuring for nitroglycerine and stabilizers at various points in close proximity to the liner is used to determine the rate and concentration of the transfer. This information is used to determine the long term effects of storage in different conditions, such as temperature and relative humidity.
Optical probes are highly useful in determining the characteristics of propellant and the relative concentration of nitroglycerine and other compounds. An optical probe uses light to determine relative concentrations of propellant stabilizer. A precisely positioned light beam is emitted from a hepta plex fiber optic probe onto the propellant surface to be examined. The incident light is reradiated from the propellant surface, captured by a single optical fiber and conveyed to a device, which compares transmitted and received light over a given spectral range. The relative level of stabilizer present is determined from the spectral deltas at the stabilizer characteristic absorption wavelength.
Broadly, the present invention is an apparatus for positioning an object in a remote location with a high degree of precision and stability. More specifically, the present invention is an apparatus for positioning an optical probe in a propellant bore hole. Also, the present invention is equipped to measure the exact position of an optical probe, so that exact position may be repeated for future measurements to accurately determine the aging characteristics of the propellant. A preferred embodiment of the present invention is positioned using an outer bar and an inner bar connected by parallel rails, an upper bar, and a pressure foot. A base is slidably attached to the rails and a probe positioning rod is attached to the base. A vernier assembly is used to precisely position the base. An analytical device holder is rotatably mounted on a support on the base to analyze the characteristics of a test subject at various points without adjusting the base or vernier assembly.
One object of the present invention is to provide a mechanism for positioning an object with a high degree of specificity and repeating the position for future use.
Another object of the present invention is to provide an apparatus that may position an analytical device in a wide variety of areas with a high degree of precision.
Another object of the present invention is to provide an apparatus that may be positioned in various locations within a propellant bore hole for the purpose of measuring various characteristics of the propellant.
Another object of the present invention is to provide an apparatus that creates stability, while minimizing the potential damage to an object being measured.
Yet another object of the present invention is to provide a mechanism for positioning an optical probe.
A very specific object of the invention is to precisely measure the position of an optical probe in a propellant bore hole, so that the position may be duplicated for future measurements.